What is the partial pressure of oxygen collected over water if the temperature is 20.0°C and the total gas pressure is 735 mmHg?

Question

Wyatt Atkins · Accepted Answer

#"718 mmHg"#

The key here is to understand that water vapor will mix with the oxygen that has gathered over the water.

This indicates that the mixture's *total pressure8 will consist of two parts.

The vapor pressure of water at that temperature is approximately #"14.47 mmHg"#

vaporpressurewater.php at https://tutor.hix.ai

Thus, you will have

#P_"total" = P_"oxygen" + P_"water"#

#P_"oxygen" = "735 mmHg" - "17.47 mmHg" = color(green)("718 mmHg")#

Noah Aldrich · Answer

undefined To find the partial pressure of oxygen collected over water at 20.0°C and a total gas pressure of 735 mmHg, you would use Dalton's Law of Partial Pressures. First, determine the vapor pressure of water at 20.0°C, which is 17.5 mmHg. Then, subtract the vapor pressure of water from the total gas pressure to find the partial pressure of oxygen:

Partial pressure of oxygen = Total gas pressure - Vapor pressure of water
Partial pressure of oxygen = 735 mmHg - 17.5 mmHg = 717.5 mmHg